4.—Each of the following persons shall for the purposes of this Act be a national of Sáorstat Eireann that is to say:—
(a) a person born in Saorstát Eireann or in the area now comprised in Saorstát Eireann;
(b) a person born outside Saorstát Eireann or the area now comprised in Saorstát Eireann whose mother at the time of his birth was ordinarily resident in Saorstát Eireann or such area;
(c) a person who at the relevant time is and for not less than five consecutive years immediately preceding that time has been ordinarily resident in Saorstát Eireann.
